Stacked plate heat exchangers are known wherein a stack of plates are provided, with flow paths for the fluids of the heat exchanger defined between adjacent pairs of the plates in the stack. Typically, the plates will have inlet and outlet manifolds for each of the fluids of the heat exchanger, with the inlet and outlet manifolds being defined by aligned openings in the plates of the stack. Some of the stacked plate heat exchangers utilize embossed plates in the stack and a further subset of these heat exchangers are so-called housingless heat exchangers wherein the plates have peripheral flanges that cooperate to enclose the various flow paths for the fluids of the heat exchanger. Because such heat exchangers can be produced in a rather efficient and cost savings manner, there is a continuing desire to improve these heat exchangers.